The 3-omega-method can be used to measure the thermal conductivity of non-electronically conductive materials. With this method, a periodically oscillating power is fed into the measurement object. The thermal conductivity is calculated using an approximate equation resulting from the periodic temperature gradation of the measurement object.
The developed measurement device measures the periodic temperature gradation for this method. Up to 8 temperature probe can be connected to the instrument. The communication between the temperature sensors and the instrument can be via SPI- or I2C bus. The instrument automatically determines which communication the sensor uses and sends the data via USB port to the connected computer. With the program Matlab the data ist read and displayed in real time.
For temperature measurement a high-accuracy digital sensor (ADT7320, SPI or ADT7420, I2C), with a typical accuracy of 0.0017 °C at 3 volt supply voltage, is used.

Keywords: temperature measurement, 3-omega-method, thermal conductivity

September 30, 2013